Okay, folks, I've been pulling my hair out over this one all afternoon: Our GeoEvent deployment receives data from our Geotab AVL system, which comes along with a handful of its own definitions that can't be edited and I need information from two of them to be fed through to a feature service hosted in our Portal. "No big deal!", I think, as I know there's an Event Joiner processor that I can use to combine the two definitions. That works great, except for when I go to publish the necessary Update Feature output. I'm able to publish the feature service just fine, but where I run into trouble is when I go to assign the Unique Feature Identifier Field via dropdown in the output configuration page the available fields all have their names truncated. Not only does this make it extremely difficult for me to choose what I think is the correct field, but GeoEvent doesn't recognize them either, and I get error log entries about how the field I've chosen as the unique identifier can't be found. This is the show stopper.
I've also tried adding in a Field Mapper processor after the Event Joiner processor in order to write to a definition that has shorter field names that don't get lobbed off in the output configuration window, but then I get error messages about the Track ID getting dropped and nothing but null values past the Field Mapper (but with good data going into it).
I'm stumped. Anyone have any insight? I've added a few images showing what's going on.